No more nuclear bombs

With the UK about to renew Trident at a cost of £20 billion I was wondering if we should bother. We're never going to fire them and do they really work as a deterrent any more? It's more likely the global outrage of launching a nuclear weapon and the rest of the world invading and wiping you out would keep anyone in line.

Just put together some cardboard versions, tell everyone they're real and save the £20 billion. Same result, less money.